2008 Lexus IS 250 AWDFACTORY OEM SERVICE PROCEDURE

How To Proceed With Troubleshooting

HINT:

  • Use this procedure to troubleshoot the power window control system.
  • The Techstream should be used in steps  3 and  5.
  1. VEHICLE BROUGHT TO WORKSHOP 
  2. CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK 
  3. CHECK COMMUNICATION FUNCTION OF MULTIPLEX COMMUNICATION SYSTEM (BEAN) 

    HINT:

    See HOW TO PROCEED WITH TROUBLESHOOTING

    1. Use the Techstream to confirm normal function of the multiplex communication system.
      1. (ECU unconnected, communication line malfunctioning) Without code outputs, proceed to A.
      2. (ECU unconnected, communication line malfunctioning) With code outputs, proceed to B.

    B:  Go to MULTIPLEX COMMUNICATION SYSTEM

    A: Go to Next Step 

  4. PROBLEM SYMPTOMS TABLE 

    HINT:

    See PROBLEM SYMPTOMS TABLE 

  5. OVERALL ANALYSIS AND TROUBLESHOOTING 
    1. Data list/Active test

      HINT:

      See DATA LIST / ACTIVE TEST 

    2. Circuit inspection
    3. Terminal of ECU

      HINT:

      See TERMINALS OF ECU 

  6. ADJUST, REPAIR OR REPLACE 
  7. RESET POWER WINDOW MOTOR 

    HINT:

    See INITIALIZATION 

    NEXT: END 

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.